
#include <cstdio>
#include <cstdlib>
#include <cstdbool>
#include <cassert>
#include <bits/stdc++.h>
using namespace std;

class B
{
private:
    int b_private;

protected:
    int b_protected;

public:
    int b_public;
};

class A
{
    B b_obj; // 组合关系

private:
    int a_private;

protected:
    int a_protected;

public:
    int a_public;

public:
    void accessB()
    {
        b_obj.b_public = 10;
        // b_obj.b_protected = 10; no
        // b_obj.b_private = 20; no
    }

    void accessA()
    {
        // b_obj.a_public = 10; 类 "B" 没有成员 "a_public"
    }
};